Precombustion chamber nozzle for internal-combustion engines



May 4, 1954 ELsTl 2,677,356

G. Pl PRECOMB TION CHAMBE OZZLE INTE L-COMBUSTION ENGINE Filed Dec. 28, 1951 2 Shets-Sheet l mvem Cra/smv PlEL c K ATTDRNE YS G. ELSTICK CHAM COMBUST May 4, 1954 2,677,356 PRECOMBUSTI NozzLE FOR INTERNAL- N ENGINES 2 Sheets-Sheet 2 Filed Dec. 28, 1951 INVENTUR Crt/'SRV PIELSHLK ATmRNEYS Patented May 4, i954 ireo STATES TENT OFFICE PRECOMBUSTION CHAMBER NOZZLE FOR INTERNAL-COMBUSTION ENGINES Claims priority, application France February 22, 1951 (Cl. 12B-32) 9 Claims.

Up to now precombustion nozzles of known types comprised a cylindrical portion held in the cylinder head on a shoulder or seat by means of a screw nut.

As the bottom of the nozzle as well as that portion thereof which is formed with a plurality of orifices project through a certain distance inside the actual combustion chamber, they were both exposed to high temperatures. Moreover, the relatively thin walls left between adjacent orifices of the nozzle were subjected during the power stroke to tensile stresses due to the diiference in pressure between the precombustion chamber and the principal combustion chamber.

In addition, the same nozzle material between adjacent oriiices was liable to considerable deformation on account of the rigid connection with the bottom of the nozzle and this frequently constituted incipient fractures, especially under heavy duty and R. P. M. conditions.

Besides, the surface tension developed on the inner walls of the nozzle are a frequent source of erosion which may also contribute to the rapid destruction of the nozzle. In View of avoiding these inconveniences the total surface of the orifices was reduced within possible limits in order to keep the metal to a sufficient cross-sectional value. However, this measure is inadequate in that it increases the losses of pressure between the precombustion chamber and the principal chamber, thereby contributing to the increase in fuel consumption.

It is the object of the present invention to avoid all the above-disclosed drawbacks by the provision of a nozzle characterized in that it comprises a main hollow body the lower portion of which is formed with substantially lateral orifices whereby the body is connected with the principal combustion chamber, a member closing and plugging the bottom end of the aforesaid hollow body by bearing upon the inner wall of this hollow body at a level above that of the said lateral orifices.

According to another feature of this invention the closing and plugging member consists of a solid base adapted to plug the bottom end of the hollow body and of a plurality of substantially vertical and radial walls acting as channels for the passage of fuel therethrough.

The bottom end of the closing member terminates with a screw-threaded portion adapted to be engaged by a corresponding screw nut or similar member in order to clamp this closing member against the hollow body.

According to a modified embodiment, the bottom end of the closing member terminates with a screw-threaded portion adapted to be screwed directly into a tapped hole formed for this purpose in the bottom end of the aforesaid hollow body.

The attached drawings illustrate diagrammatically by way of example preferred embodiments of the invention. In the drawings:

Fig. 1 is a longitudinal section of a nozzle according to this invention mounted in the cylinder head of an engine;

Fig. 2 is a cross-sectional view of same according to the line II-II;

Fig. 3 is a view similar to Fig. 1 showing a modified embodiment.

Referring first to the embodiment illustrated in Figs. 1 and 2 the cylinder head of the engine is designated at l, the cylinder at 2 and the piston at 3. The principal combustion chamber is shown at il, and 5 is the central prechamber or central precombustion chamber.

This prechamber is formed with an aperture 6 in which a nozzle l is held in position for instance by means of a screw-threaded ring nut 8.

The nozzle l comprises a substantially cylindrical portion or sleeve 9 the lower extension of which consists of a tapered portion I0 in which peripheral orifices H are formed.

The nozzle bottom is closed by a so-called plug member l2 consisting of a base I3 formed with a screw-threaded portion I4 and of an upper portion constituted by substantially vertical and radial walls l5 as shown. These walls may be either straight or warped.

These walls form channels I6 (see Fig. 2) through which the fuel may flow freely to the orifices Il.

The same walls I5 are formed with tapered peripheral faces Il engaging the inner faces of corresponding taper of the walls I0 of the nozzle l. A screw nut i8 engaging the screw-threaded portion I4 causes the closing member l2 tightly to engage the lower portion Ill of the nozzle.

It is obvious that the stress resulting from the tightening of the closing member is supported by the radial walls i5 positioned above the level of the orifices il.

From the foregoing it will be seen that in this novel nozzle design the portion thereof above the orifices is reinforced by a detachable member, thereby relieving the nozzle material between the orices from any stresses due to differences in pressure between the combustion chambers While permitting the free thermal expansion of the cylindrical nozzle body. With this particular arrangement the lower portion of the nozzle,

which is subjected to high thermal loads, is relieved from any other tensions and the corrosive effect is no more to be feared. The central fuel jet is directed onto the insert or detachable member, thereby avoiding any deformation of the cylindrical nozzle.

Since the nozzle is free from any additional stresses it becomes possible to increase the area of the orices and the cross-section of the cylindrical portion 9 in View of reducing the losses of pressure.

Inthe modied embodiment shown in Fig. 3 the nozzle 1 is formed at its bottom end with a threaded hole i9 in which the screw-threaded portion i4 of the member I2-l3 is screwed directly.

Of course, the invention is not limited to the specific embodiments illustrated in the drawings and described 'hereinabove as these are given for illustrative purpose only.

What I claim is:

l. Nozzle for precombustion chambers adapted for use in internal combustion engines comprising a main hollow body, lateral orifices on the lower portion of said body and another orice in the bottom thereof, a member adapted to close or plug the orifice in the bottom of aforesaid hollow body, supporting means on said plug member bearing against the inner face of said body above and below the said lateral orifices, said inner face having a generally tapered shape.

2. Nozzle according to claim l wherein said closing member has a screw threaded end portion protruding at the end of the hollow body and a member screwed thereon for tightening this member against the hollow body.

3. Nozzle according to claim 1 wherein the closing member comprises a solid bottom portion or base adapted to obturate the orice on the bottom of the hollow body and at its upper part a plurality of substantially vertical and radial partitions constituting the said supporting means and forming channels for the passage of fuel.

4. Nozzle according to claim 3 wherein the substantially vertical and radial walls are straight.

5. Nozzle according to claim 3 wherein substantially tapered bearing surfaces are provided in said hollow body for engaging the substantially vertical and radial partitions which are correspondingly tapered.

6. Nozzle according to claim 3 wherein the closing members comprises three radial partitions forming with the inner face of the hollow body three fuel passages.

7. Nozzle according to claim 1 wherein the hollow body consists of an upper substantially cylindrical portion terminating in a practically tapered lower portion provided with said lateral orifices.

8. Nozzle according to claim 7 wherein the wall thickness of said tapered lower portion of the hollow body is substantially the equivalent of the diameter of the lateral orices provided therein.

9. Nozzle according to claim rI wherein the said lateral orifices are substantially in alignment with the channels provided between said partitions.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,136,818 Leissner Apr. 20, 1915 1,700,903 Marburg Feb. 5, 1929 

